regulates regulation of heparan sulfate proteoglycan biosynthetic process https://github.com/geneontology/go-ontology/issues/29745 GO:0010908 biological_process Any process that modulates the rate, frequency or extent of heparan sulfate proteoglycan biosynthesis. Heparan sulfate proteoglycan biosynthetic processes are the chemical reactions and pathways resulting in the formation of the heparan sulfate proteoglycan, which consists of a core protein linked to a heparan sulfate glycosaminoglycan. The heparan sulfate chain is composed of the repeating disaccharide unit beta-(1,4)-N-acetyl-D-glucosamine-alpha-(1,4)-hexuronic acid. heparan sulfate proteoglycan biosynthetic process biological regulation regulation of protein O-linked glycosylation